1. Technical Field
The present disclosure relates generally to a marking device for identifying the location of a surgical site and, more specifically, a marking device which is insertable through a biopsy needle to position a marking hoop at a biopsy site.
2. Background of Related Art
Devices for marking lesions within the body are well known in the art. These devices generally include a cannula which is inserted into the body under local anesthesia to a position adjacent and/or in contact with the lesion. A wire marker is passed through the cannula and is anchored to the lesion so that the lesion is marked for subsequent surgical procedures such as excision or biopsy. After marking the lesion, the cannula is usually removed leaving the wire in place and extending from the body.
One problem associated with these devices is that the wire markers tend to dislodge and migrate during transport of the patient to undergo the subsequent surgical procedure.
U.S. Pat. No. 5,018,530 (xe2x80x9cthe ""530 patentxe2x80x9d) discloses a wire needle assembly designed to overcome this problem. The ""530 patent attempts to solve the above-identified problem by providing a marker wire having a helically wound wire tip attached to a shaft which is inserted within the lumen of a cannula and then rotated into a lesion to anchor the marker within the lesion tissue. One disadvantage of the ""530 patent wire needle assembly is that the marker wire helix is too large in diameter to fit down the smaller biopsy cannulas. Moreover, some migration of the marker wire may still occur.
U.S. Pat. No. 5,221,269 (xe2x80x9cthe ""269 patentxe2x80x9d) also discloses a device for marking the locating of a lesion. The device includes an introducer needle and a wire guide which is passed through a passageway in the introducer needle. The wire guide has a straight portion and a distal portion preformed into a resilient helical coil. When positioned in the passageway of the introducer needle, the preformed distal portion assumes an unwound configuration. The wire guide can be advanced distally from the introducer needle to mark the location of a lesion.
One problem associated with the device disclosed in the ""269 patent is that there is no structure disclosed for accurately advancing the wire guide into the lesion. Thus, if the wire guide is inserted too deeply into the lesion such that the straight portion extends through the lesion, migration may still occur. Moreover, because the adjacent coils of the helical wire guide are spaced, migration of the wire guide may still occur even if the wire guide is properly positioned.
Accordingly, a need exists for a site marking device for identifying the location of a surgical site or lesion which is capable of accurately positioning a marker which will not migrate adjacent the surgical site.
In accordance with the present disclosure, a site marker assembly including a site marker device and a marker are provided. The site marker device includes a housing having a bore. A delivery tube is secured to a forward end of the housing and extends distally therefrom. A rod pusher is movably positioned within the delivery tube. An actuator including a plunger is movably positioned within the housing and is operably connected to the rod pusher. The plunger is movable from a first position to a second position to advance the rod pusher through the delivery tube and eject a marker from the distal end of the delivery tube.
In an alternate embodiment, an elongated tubular body is positioned about the delivery tube and the actuator further includes an inner housing movably positioned within the housing. The inner housing defines a bore in which the forward end of the plunger is positioned. The actuator is operably connected to the rod pusher and the delivery tube to provide two stage advancement. During the first stage of advancement, the rod pusher and the delivery tube are advanced through the distal end of the elongated tubular body. During the second stage of advancement, the rod pusher is advanced independently of the delivery tube to eject a marker from the delivery tube.
The marker is formed from a shape memory material such as tinel and has a circular or hoop configuration. The ends of the hoop are closely aligned or stacked to prevent migration of the hoop with respect to a lesion.